I was checking a test app in valgrind and much to my surprise it was complaining about a memleak in libmicrohttpd.

In check_argument_match() a buffer is allocated using strdup() but freed nowhere.

I wouldn't have noticed this leak if it wasn't for valgrind because if a URI is requested without any arguments (my usual case)
the buffer that gets allocated has 'only' a length of 1 byte, thus memory usage will build up very slowly over time.

The patch attached fixes it.
Btw. the indentation of that file is a mess, tabs and spaces are mixed :-|

Regards,
Andreas

ChangeLog

@@ -1,3 +1,6 @@
+Thu Jun  4 13:37:05 CEST 2015
+	Fixing memory leak in digest authentication. -AW
+
 Wed Jun 03 21:23:47 CEST 2015
 	Add deprecation compiler messages for deprecated functions 
 	and macros. -EG

src/microhttpd/digestauth.c

@@ -508,7 +508,10 @@ check_argument_match (struct MHD_Connection *connection,
 						 connection,
 						 argp);
 	  if (MHD_YES != test_header (connection, argp, NULL))
-	    return MHD_NO;
+      {
+        free(argb);
+        return MHD_NO;
+      }
 	  num_headers++;
 	  break;
 	}
@@ -527,10 +530,16 @@ check_argument_match (struct MHD_Connection *connection,
 					     connection,
 					     equals);
       if (! test_header (connection, argp, equals))
-	return MHD_NO;
+      {
+          free(argb);
+          return MHD_NO;
+      }
+      
       num_headers++;
       argp = amper;
     }
+    
+  free(argb);
 
   /* also check that the number of headers matches */
   for (pos = connection->headers_received; NULL != pos; pos = pos->next)